1. Field of the Invention
The present invention relates to apparatus and method for aligning the front toe planes of a motor vehicle and, more particularly, in a preferred embodiment, to apparatus and methods for automatically aligning the front toe planes of a motor vehicle so as to minimize tracking errors of the front wheels with respect to the rear wheels.
2. Description of the Prior Art
An illustrative environment where application of the principles of the present invention is particularly advantageous is in wheel alignment systems for automobile manufacturer's use such as, for example, the vehicle front end alignment system for measuring camber and toe as described in U.S. Pat. No. 4,443,951 of Elsasser et al. dated Apr. 24, 1984. There, electrical signals are derived which are indicative of amount of camber and toe-in misalignment from a single reference axis. Actual values of toe-in and camber are compared in a reference-actual value comparator and correcting magnitudes are displayed. Mechanical adjustments to correct the misalignment are performed. Such an arrangement allegedly provides suitable front end alignments with respect to the longitudinal axis of the vehicle.
Another method and apparatus for measuring toe and camber of wheels on motor vehicles is described in U.S. Pat. No. 4,457,075 of Murata dated July 3, 1984. There, toe-in of front and rear wheels are performed simultaneously with respect to two parallel predetermined vertical surfaces. Also, camber measurements are made. To perform the measurements, the vehicle must be parked parallel with the vertical reference walls. Although it appears that thrust angle parameters are used to correct for toe-in, the offset of the center line of the vehicle with respect to the vertical references appear to not be of significance in correcting for vehicle off-center steering.